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Polynomial regression calculation of the Earth's position based on millisecond pulsar timing

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Research in Astronomy and Astrophysics 2012年第2期12卷 219-234页

作者： Feng Tian 1,2.Zheng-Hong Tang 1,Qing-Zeng Yan 1,2.and Yong Yu 11 Shanghai Astronomical Observatory,chinese academy of {2.,Shanghai 2.0030,china 2.graduate University of chinese academy of sciences,Beijing 100049,china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China graduate University of chinese academy of sciences Beijing 100049 China

Prior to achieving high precision navigation of a spacecraft using X-ray observations, a pulsar rotation model must be built and analysis of the precise posi- tion of the Earth should be performed using ground pulsar timing observations. We can simulate time-of-arrival ground observation data close to actual observed values before using pulsar timing observation data. Considering the correlation between the Earth＇s position and its short arc section of an orbit, we use polynomial regression to build the correlation. Regression coefficients can be calculated using the least square method, and a coordinate component series can also be obtained; that is, we can calcu- late Earth＇s position in the Barycentric Celestial Reference System according to pulse arrival time data and a precise pulsar rotation model. In order to set appropriate param- eters before the actual timing observations for Earth positioning, we can calculate the influence of the spatial distribution of pulsars on errors in the positioning result and the influence of error source variation on positioning by simulation. It is significant that the threshold values of the observation and systematic errors can be established before an actual observation occurs; namely, we can determine the observation mode with small errors and reject the observed data with big errors, thus improving the positioning result.

关键词： autonomous positioning - millisecond pulsar - pulsar timing - re-gression analysis

Preparation of Pt/K_2.a_2.i_3O_(10) and its photo-catalytic activity for hydrogen evolution from methanol water solution

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Science china Chemistry 2006年第2期49卷 162-168页

作者： CUI Wenquan1,3, LIU Li2. FENG Liangrong1, XU Chenghua1, LI Zijian1, Lü Shaojie1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, chinese academy of sciences, Chengdu 610041, china 2. Chemistry Department, Sichuan University of Science & Engineering, Zigong 643033, china 3. graduate school of the chinese academy of sciences, Beijing 100039, china Correspondence should be addressed to Qiu Fali 1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China 3. graduate school of the{2. Beijing 100039 China 2. Chemistry Department Sichuan University of Science & Engineering Zigong 643033 China

A layered perovskite-type oxide K2.a2.i3O10 was prepared with high-temperature solid-state reaction, and characterized with X-ray diffraction (XRD) and ultraviolet-visible diffuse re-flectance spectroscopy (UV-Vis DRS). Platinum was loaded onto K2.a2.i3O10 as a co-catalyst with different methods. The dispersion of platinum on K2.a2.i3O10 was determined with HOT method. The photocatalytic activity of Pt/K2.a2.i3O10 was studied. This catalyst showed much higher activity in hydrogen evolution reaction than Ni/K2.a2.i3O10. The effects of different amounts of loaded platinum and several preparation methods were evaluated. The best achieved hydrogen evolution rate was 2.3.88 μmol·h?1 by Pt(2.)/K2.a2.i3O10. A possible band structure and mechanism were discussed based on the results.

关键词： photocatalysis hydrogen platinum K_2.a_2.i_3O_(10) support

Mass Spectrometric Evidence of Heparin Disaccharides for the Catalytic Characterization of A Novel Endolytic Heparinase

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Acta Biochimica et Biophysica Sinica 2004年第12期36卷 840-844页

作者： Yapeng CHAO1,3, Shaoxiang XIONG2. Xiulan CHENG1, and Shijun QIAN1* 1Institute of Microbiology, chinese academy of sciences, Beijing 100080, china 2.enter of Mass Spectrometry, Institute of Chemistry, chinese academy of sciences, Beijing 100080, china 3graduate school of the chinese academy of sciences, Beijing 100039, china Institute of Microbiology Chinese Academy of SciencesBeijing 100080 China graduate school of the{2.Beijing 100039 China Center of Mass Spectrometry Institute of Chemistry Chinese Academy of SciencesBeijing 100080 China

Heparinase from different sources can eliminate heparin or/and heparan sulfate into various low-molecular weight heparins with different characteristics. Porcine intestinal mucosa heparin was de- graded into a series of oligosaccharides by a novel heparinase from the species Sphingobacterium. Disaccha- ride components from the digests were separated and purified by ultrafiltration and HPLC. Five major peaks appeared as three types according to their retention time. The mass spectrometry of peak I mainly gave the non-sulfated disaccharide with the mass of 379 Da. Peak II and III were indicated as two major monosulfated disaccharides with molecular mass of 417 and 459 Da respectively. Moreover, the peak III represented an N- acetyl disaccharide. Both peak IV and V showed the same mass of 496 Da, hinting that they were disulfate- substituted disaccharides. No trisulfate-substituted disaccharides were detected in the mixture of the heparin digest though they were abundant in the heparin structure. The results revealed that the heparinase might specifically cut the sites with low sulfated domain in heparin.

关键词： electrospray ionization-mass spectrometry heparin disaccharides heparinase high perfor- mance liquid chromatography Sphingobacterium sp.

Study on growth and properties of novel γ-LiAlO_2.substrate

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Science china(Technological sciences) 2006年第2期49卷 188-193页

作者： ZOU Jun1,2. ZHOU Shengming1, XU Jun1 & ZHANG Rong3 1. Shanghai Institute of Optics and Fine Mechanics, chinese academy of sciences, Shanghai 2.1800, china {2. of chinese academy of sciences, Beijing 100039, china 3. Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 2.0093, china 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China 2. graduate school of chinese academy of sciences Beijing 100039 China 3. Laboratory of Solid State Microstructures and Department of Physics Nanjing University Nanjing 210093 China

Transparent γ-LiAlO2.single crystal has been grown by Temperature Gradient technique. The surface of the wafer annealed in O2.atmosphere at 1100°C for 70 h became opaque and Li-poor phase (LiAl5O8); while, that annealed in Li-rich atmosphere kept transparent and smooth. The full-width at half maximum value dropped to 30 arcsecs when the wafer was annealed in Li-rich atmosphere. That annealed in O2.atmosphere increased to 78 arcsec. Compared with absorption spectra, we can conclude that the 196 nm absorption peak was caused by Li vacancies and the 736 nm peak was caused by O vacancies.

关键词： γ-LiAlO2 crystal, scanning electron micrograph (SEM), absorption spectra.

The relation between black hole masses and Lorentz factors of the jet components in blazars

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Research in Astronomy and Astrophysics 2009年第3期9卷 293-301页

作者： Ming Zhou1,2.3 and Xin-Wu Cao1,2.1 Shanghai Astronomical Observatory, chinese academy of sciences, Shanghai 2.0030, china 2.Joint Institute for Galaxy and Cosmology (JOINGC) of SHAO and USMC, Shanghai 2.0030, china 3 graduate school of the chinese academy of sciences, Beijing 100049, china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Joint Institute for Galaxy and Cosmology (JOINGC) of SHAO and USMC Shanghai 200030 China graduate school of the{2. Beijing 100049 China

We explore the relationship between black hole mass (MBH) and the motion of the jet components for a sample of blazars. The Very Long Baseline Array (VLBA) 2.cm Survey and its continuation: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments (MOJAVE) have observed 2.8 radio-loud AGNs, of which 146 blazars have reliable measurements of their apparent velocities of the jet components. We calculate the minimal Lorentz factors for these sources from their measured apparent velocities, and their black hole masses are estimated with their broad-line widths. A sig- nificant intrinsic correlation is found between black hole masses and the minimal Lorentz factors of the jet components. The Eddington ratio is only weakly correlated with the min- imal Lorentz factor, which may imply that the Blandford-Znajek (BZ) mechanism may dominate over the Blandford-Payne (BP) mechanism for the jet acceleration (at least) in blazars.

关键词： black hole physics — galaxies: active — galaxies: jets — galaxies: nuclei

Transformations and non-degenerate maps

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Science china Mathematics 2005年第z1期48卷 195-205页

作者： LI Baokui & WANG Yuefei Institute of Mathematics, academy of Mathematics and System sciences,{2., Beijing 100080, china graduate school,{2., Beijing 100080, china 1. Institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences 100080 Beijing China 2. graduate school Chinese Academy of Sciences 100080 Beijing China

We shall prove the equivalences of a non-degenerate circle-preserving map and a M(o)bius transformation in ^Rn, of a non-degenerate geodesic-preserving map and an isometry in Hn of a non-degenerate line-preserving map and an affine transformation in Rn. That a map is non-degenerate means that the image of the whole space under the map is not a circle, or geodesic or line respectively. These results hold without either injective or surjective, or even continuous assumptions, which are new and of a fundamental nature in geometry.

关键词： M(o)bius transformation, circle-preserving map, non-degenerate map.

Possible Energy Network with polygeneration system and CCS for china

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中国科学：技术科学英文版 2010年第1期53卷 33-39页

作者： GAO Lin1,LI Sheng1,2.JIN HongGuang1 & LIN Hu1 1 Institute of Engineering Thermophysics,chinese academy of {2.,Beijing 100190,china 2.graduate school of chinese academy of sciences,Beijing 100039,china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Graduate School of Chinese Academy of Sciences Beijing 100039 China

On basis of adopting polygeneration systems for power and alternative fuels,capturing CO2.with near zero energy penalties,and storing CO2.on sites,a new kind of Energy Network can integrate energy utilization,CO2.capture,transportation and storage ***-economic analysis of this solution focusing on Inner Mongolia and the Yangtze River Delta districts had been carried with comparison to the chain method for energy utilization and CO2.*** solution can save 2..5% of energy,and reduce 35% of total *** adoption of advanced polygeneration systems contributes 52.2. of the total saved costs,and the integration of energy utilization and CO2.sequestration in the Energy Network contributes 47.8%.From the aspect of CCS,the CO2.sequestration cost in the Energy Network can be as low as 12.$/t due to the lower energy penalties of capture in polygeneration systems and the combination of CO2.source and *** Energy Network exhibits attractive performance on energy saving,costs reduction for CCS,which may be a promising solution for sustainable development of china.

关键词： CO2 capture and storage Energy Network polygeneration system

Rational redesign of inhibitors of furin/kexin processing proteases by electrostatic mutations

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Acta Pharmacologica Sinica 2004年第12期25卷 146-152页

作者： Xiao-hui CAI, Qing ZHANG, Da-fu DING2.Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological sciences, chinese academy of sciences, {2. school of the chinese academy of sciences, Shanghai 2.0031, china Key Laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Shanghai 200031 China

AIM: To model the three-dimensional structure and investigatethe interaction mechanism ofthe proprotein convertase furin/kexin and their inhibitors (eglin c mutants). METHODS: The three-dimensional complex structures of furin/ kexin with its inhibitors, eglin c mutants, were generated by modeller program using the newly published X-ray crystallographical structures of mouse furin and yeast kexin as templates. The electrostatic interaction energy of each complex was calculated and the results were compared with the experimentally determined inhibition con- stants to find the correlation between them. RESULTS: High quality models of furin/kexin-eglin c mutants were obtained and used for calculation of the electrostatic interaction energies between the proteases and their inhibitors. The calculated electrostaticenergies of interaction showeda linear correlation to the experimental inhibition constants. CONCLUSION: The modeled structures give good explanations of the specificity of eglin c mutants to furin/ kexin. The electrostatic interactions play important roles in inhibitory activity of eglin c mutants to furin/kexin. The results presented here provided quantitative structural and functional information concerning the role of the charge- charge interactions in the binding of furin/kexin and their inhibitors.

关键词： furin kexin eglin c drug design electrostatic mutation

Spatial heterogeneity of the driving forces of cropland change in china

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Science china Earth sciences 2005年第12期48卷 2231-2240页

作者： LIU Xuhua1,2. WANG Jinfeng1, LIU Mingliang4,1 & MENG Bin1,2.3 1. Institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101,{2. 2. graduate school of the chinese academy of sciences, Beijing 100039,{2. 3. College of Arts and sciences of Beijing Union University, Beijing 100083,{2. 4. school of Forestry and Wildlife sciences, Auburn University, Auburn, Alabama, AL36849, USA 1. Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. graduate school of the chinese academy of sciences 100039 Beijing China 3. school of Forestry and Wildlife sciences Auburn University Auburn AL36849 Alabama USA 4. College of Arts and sciences of Beijing Union University 100083 Beijing China

By using digital satellite remote sensing data acquired in 1987―1989 and 1999―2.00 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in china. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of china, natural condition changes and geographical background were the main constraints and drivers, while in Eastern china, social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in china recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

关键词： land use change, driving force, integrated classification, spatial statistics, cropland, china.